两种实时定量PCR技术检测肺泡灌洗液中结核分枝杆菌DNA的比较研究

A comparative study on the detection of Mycobacterium tuberculosis complex DNA in bronchoalveolar lavage fluid by two Real-time PCR

目的比较结核分枝杆菌及利福平耐药快速检测技术（简称Xpert MTB/RIF）和达安实时定量PCR检测肺泡灌洗液中的结核杆菌DNA对肺结核的诊断和卫生经济学价值。方法招募2014年3月~2015年11月进入第四军医大学西京医院就诊的疑似肺结核的连续病例112例,收集肺泡灌洗液样本同时进行抗酸染色、MGIT960液体培养和药敏试验、Xpert MTB/RIF和达安实时定量PCR检测。结果 112例纳入的研究对象中经培养确诊的肺结核患者有53例,疑似的肺结核患者15例,非结核患者44例。以MGIT960液体培养为金标准,Xpert MTB/RIF与达安实时定量PCR的灵敏度差异无统计学意义（98.11%vs90.57%,P=0.205）,两者的灵敏度均高于抗酸染色灵敏度58.49%（P〈0.001）;而若以临床诊断为参考标准,Xpert MTB/RIF的灵敏度则高于达安实时定量PCR,且差异有统计学意义（P=0.045）。而抗酸染色、达安实时定量PCR和Xpert MTB/RIF的特异性分别为99.73%、88.64%和95.45%,差异无统计学意义（P=0.184）。进行成本-效果分析,每检出1例肺结核行1次Xpert MTB/RIF的费用为1 033.85元,远远高于达安实时定量PCR费用196.49元。结论 Xpert MTB/RIF灵敏度高,操作更加简便快速且易于开展,并能同时检测利福平耐药性,可作为检测肺泡灌洗液中结核分枝杆菌DNA的首选方法。但达安实时定量PCR的检测成本较低,更加适用于低收入人群。

Objective To compare the diagnostic performance and cost of Xpert MTB/RIF and Da′an quantitative real-time PCR for detection of Mycobacterium tuberculosis complex DNA in bronchoalveolar lavage fluid（BALF）. Methods A total of 112 consecutive patients with suspected pulmonary tuberculosis were recruited in Xijing Hospital of the Fourth Military from March 2014 to November 2015.BALF samples were collected and tested by Ziehl-Neelsen staining,MGIT960 liquid culture and for drug susceptibility.Bacterial DNA was determined by Xpert MTB/RIF and Da′an real-time PCR. Results Of the 112 patients enrolled in the study,53 were confirmed by bacterial culture as pulmonary tuberculosis,15 patients were clinically suspected pulmonary tuberculosis and 44 were determined as non-tuberculosis patients.When using MGIT 960 liquid culture as a reference standard,there was no significant difference between the sensitivity of Xpert MTB/RIF and Da′an real-time PCR（98.11%vs 90.57%,P=0.205）,which were both higher than that of Ziehl-Neelsen staining58.49%（P0.001）.When using clinical diagnosis as a reference standard,the sensitivity of Xpert MTB/RIF was significantly higher than that of Da′an real-time PCR（P = 0.045）.No significant differences were found among the specificities of the above three methods（P=0.184）.Based on the cost effectiveness analysis,the single time cost of per pulmonary tuberculosis patient by Xpert MTB/RIF is 1 033.85 yuan,much higher than that of Da′an real-time PCR（196.49yuan）. Conclusions Xpert MTB/RIF is a simple and fast method with high sensitivity for the detection of Mycobacterium tuberculosis DNA in BALF specimen;it can simultaneously detect rifampin resistance.While the cost of Da′an real-time PCR is lower which is more suitable for low income patients.